Re: [PATCH v2] usb: typec: fusb302: Fix masking of comparator and bc_lvl interrupts

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Mon, Nov 08, 2021 at 11:28:32AM +0100, Ondrej Jirman wrote:
> The code that enables either BC_LVL or COMP_CHNG interrupt in tcpm_set_cc
> wrongly assumes that the interrupt is unmasked by writing 1 to the apropriate
> bit in the mask register. In fact, interrupts are enabled when the mask
> is 0, so the tcpm_set_cc enables interrupt for COMP_CHNG when it expects
> BC_LVL interrupt to be enabled.
> 
> This causes inability of the driver to recognize cable unplug events
> in host mode (unplug is recognized only via a COMP_CHNG interrupt).
> 
> In device mode this bug was masked by simultaneous triggering of the VBUS
> change interrupt, because of loss of VBUS when the port peer is providing
> power.
> 
> Fixes: 48242e30532b ("usb: typec: fusb302: Revert "Resolve fixed power role contract setup"")
> Signed-off-by: Ondrej Jirman <megous@megous.com>
> Cc: Hans de Goede <hdegoede@redhat.com>

Should this go to stable?

Acked-by: Heikki Krogerus@linux.intel.com

> ---
>  drivers/usb/typec/tcpm/fusb302.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 7a2a17866a823..72f9001b07921 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -669,25 +669,27 @@ static int tcpm_set_cc(struct tcpc_dev *dev, enum typec_cc_status cc)
>  		ret = fusb302_i2c_mask_write(chip, FUSB_REG_MASK,
>  					     FUSB_REG_MASK_BC_LVL |
>  					     FUSB_REG_MASK_COMP_CHNG,
> -					     FUSB_REG_MASK_COMP_CHNG);
> +					     FUSB_REG_MASK_BC_LVL);
>  		if (ret < 0) {
>  			fusb302_log(chip, "cannot set SRC interrupt, ret=%d",
>  				    ret);
>  			goto done;
>  		}
>  		chip->intr_comp_chng = true;
> +		chip->intr_bc_lvl = false;
>  		break;
>  	case TYPEC_CC_RD:
>  		ret = fusb302_i2c_mask_write(chip, FUSB_REG_MASK,
>  					     FUSB_REG_MASK_BC_LVL |
>  					     FUSB_REG_MASK_COMP_CHNG,
> -					     FUSB_REG_MASK_BC_LVL);
> +					     FUSB_REG_MASK_COMP_CHNG);
>  		if (ret < 0) {
>  			fusb302_log(chip, "cannot set SRC interrupt, ret=%d",
>  				    ret);
>  			goto done;
>  		}
>  		chip->intr_bc_lvl = true;
> +		chip->intr_comp_chng = false;
>  		break;
>  	default:
>  		break;

thanks,

-- 
heikki